Houseboat would be my guess. Not to uncommon really. Lake Shasta, Lake Powell, Lake Roosevelt etc. The twin rig part would be interesting to see though.

Ding Ding Ding, we have a winner. That was our every other year vacation to Lake Powell. It is a houseboat that we rented, we have been doing that trip for quite a few years now. We always pull our toys with the houseboat, been doing that since the first time we went back in the early 90's.